Another public service post.
Something's broken, you think it's PHP but you aren't sure and you don't want to pop up a bunch of awful errors on your site by setting:
in your wp_config.php
The solution is to add three more lines so that the whole thing writes to an error log inside of wp-content:
// Enable WP_DEBUG mode
// Enable Debug logging to the /wp-content/debug.log file
// Disable display of errors and warnings
// Use dev versions of core JS and CSS files (only needed if you are modifying these core files)